Micro-fluidics are used to manipulate fluids in channels with cross-sectional height and width that typically range from 1 to 500 micrometers or microns. Fluids are moved in volumes of nanoliters or microliters. “Lab-on-a-chip” technology has used micro-fluidics to perform chemical reactions and analyses at very high speeds while consuming small amounts of starting materials. Various chemical reactions require conditions such as high pressure and high temperatures, which may be difficult to achieve safely using conventional techniques, and micro-fluidic systems use miniaturized reactors, mixers, heat exchangers, and other processing elements for performing such chemical reactions on a miniature scale with less difficulty and more safety. Such systems are useful for reactions such as pharmaceutical or laboratory reactions where very small and accurate amounts of chemicals are necessary to successfully arrive at a desired product. Furthermore, use of micro-fluidic systems increases efficiency by reducing diffusion times and the need for excess reagents.
Applications for micro-fluidic systems are generally broad, but commercial success has been slow to develop in part because micro-fluidic devices are difficult and costly to produce. Another significant hurdle in micro-fluidics is addressing the macroscale to microscale interface. Other considerable problems include clogging of the systems, fouling of the reagent in the system, and supplying new reagent once the previous supply is depleted, clogged, or fouled. Furthermore, waste accumulations and air bubbles interfere with proper micro-fluidic system operation. Thus, there is a need for a low cost solution for micro-fluidic systems. Preferably, but not necessarily, such solution would allow easy replacement of reagent once its supply is depleted, clogged, or fouled, and allow for remotely flushing waste and air bubbles from a micro-fluidic system in order to minimize losses of costly reagent. Additionally, many reactions and mixtures require condensing and evaporation techniques that are difficult to perform on a micro- or nanoscale. As used herein, micro-fluidic and microscale are meant to describe fluidic elements that have micro-sized capillaries for transporting fluid. Such capillaries would have effective interior diameters from about 1 micron to about 500 microns. Usually a micro-fluidic element will have an interior diameter of more than 100 microns, and for many applications an inside diameter of 200 microns is a good size.
The above and other needs are met by an evaporator and concentrator in a reactor and loading system. In one embodiment, a micro-fluidic evaporator evaporates a target from a liquid solution. The evaporator has a vial with an interior volume and a first and second end. Liquid solution is disposed in the vial and extends from the second end toward the first end. The evaporator has a gas source capable of accelerating evaporation of the target and a first micro-fluidic pathway extending from the gas source to an exhaust point near the second end of the vial. The first micro-fluidic pathway inputs the gas at the exhaust point from the gas source at an input rate such that the gas effervesces through the liquid solution without substantial splashing and without exploding the liquid solution. This results in an accelerated evaporation of the target from the liquid solution producing the evaporated gas. A second fluidic pathway extends from near the first end of the vial to a location external to the vial and moves the evaporated target from the interior volume of the vial to a location external to the vial.
In some embodiments, the evaporator has a third fluidic pathway extending from the gas source to a sweep exhaust point located within the vial and adjacent to the solution but not in the solution. The third fluidic pathway inputs gas into the vial adjacent to the solution for sweeping the evaporated target through the second fluidic pathway and out of the vial. In some embodiments, the third fluidic pathway is concentric with the first micro-fluidic pathway such that the third fluidic pathway surrounds the first micro-fluidic pathway. In some embodiments, the gas source has a first and a second gas source, the first gas source being connected to the first micro-fluidic pathway and the second gas source being connected to the second fluidic pathway.
In some embodiments, the evaporator has an input supply line for inputting fluids into the vial and an output line extending from a point near the second end of the vial and within the vial to a location external to the vial. The output line exports fluid in the vial once the desired evaporation has occurred. In some embodiments the evaporator has a heater and in some it has a cooler for heating and cooling the vial respectively.
In another embodiment, an evaporator/concentrator system dries and concentrates a fluid containing ions. The system has a first vial with an interior volume and a first and second end and a first micro-fluidic pathway extending from outside the first vial to a point near the second end of the first vial. The system also has a second fluidic pathway extending from near the first end of the first vial to a location external to the first vial and a third fluidic pathway extending from a gas source to near the first end of the first vial for inputting a gas from the gas source into the first vial and out the second fluidic pathway to provide a gas sweep of the interior of the first vial. The system has an ion exchange cartridge for capturing ions and an input line for the first vial connected from the ion exchange cartridge to the first vial. A target fluid vial stores a target fluid containing target ions and provides the target fluid containing the target ions to the ion exchange cartridge. A capturing fluid vial stores a capturing fluid and provides the capturing fluid to the ion exchange cartridge.
A pump and switch valve connects the target fluid vial to the ion exchange cartridge and is configurable for pumping the target fluid from the target fluid vial through the pump and switch valve, through the ion exchange cartridge and into the first vial. The ion exchange cartridge operates to capture the target ions as the target fluid flows through the ion cartridge. The pump and switch valve also pumps the supply fluid from the first vial through the first micro-fluidic pathway and out of the first vial. Then the pump and switch valve pumps the capturing fluid from the capturing fluid vial, through the pump and switch valve and through the ion exchange cartridge into the first vial. The capturing fluid captures the target ions in the ion exchange cartridge so that the vial contains capturing fluid with target ions. Finally, the pump and switch valve connects the first micro-fluidic pathway to the gas source so that the gas flows through the first micro-fluidic pathway and effervesces the ion containing fluid and causing the water in the fluid to evaporate resulting in a concentrated ion fluid in the first vial.
In some embodiments a second vial stores a supply of anhydrous combining fluid and the pump and switch valve supplies at least some of the anhydrous combining fluid to the first vial for combining with the concentrated ion fluid to produce an anhydrous product solution. In some embodiments, the system has a dry product vial connected to the pump and switch valve for receiving the anhydrous product solution from the first vial and pumping the anhydrous product solution from the first vial to the dry product vial. In some embodiments, the dry product vial has radiation shielding.
In another embodiment, a micro-fluidic system has a pump and switch valve system that pumps fluid through the system and includes micro-fluidic tubes. The system also has a micro-fluidic concentrator including a concentrator vial for containing fluid and having a low point within the vial, the vial being configured so that the fluid flows to and collects at the low point. The concentrator also has a micro-fluidic tube extending from outside the vial to the low point in the vial to supply evaporation gas to the vial to evaporate water from fluid in the vial and thereby concentrate the fluid and withdrawing fluid from the low point in the vial. The concentrator has a sweep gas input port for supplying sweep gas into the vial at a location remote from the low point, a gas supply for supplying gases to the sweep gas input port and the micro-fluidic tube, an exhaust port in the concentrator vial for allowing gases to escape the concentrator vial, and an input port for supplying fluid to the concentrator vial. The system also has a micro-fluidic element including a micro-fluidic pathway that performs a micro-fluidic function. The pump and switch valve system pumps fluids to and from the micro-fluidic element and the micro-fluidic concentrator.
In some embodiments, the micro-fluidic element of the system is a reactor and at least two reagents are supplied by the pump and switch valve system so that the reagents are reacted in the micro-fluidic reactor and concentrated in the micro-fluidic concentrator or vice-versa. In other embodiments, the micro-fluidic element of the system is a coil of micro-fluidic tubing holding fluids and functioning as a fluid supply source and in other embodiments functioning as a reactor.